Discussion of “Practical transitions among undrained shear strengths of remolded samples from pocket penetrometer tests and other laboratory tests” by Budak T.O., Gurbuz A. and Eksioglu B. [Catena 213 (2022) 106148

Abstract

This article presents an appraisal of the recently published research paper in the Catena Journal titled “Practical transitions among undrained shear strengths of remolded samples from pocket penetrometer tests and other laboratory tests”. This paper investigated correlations on undrained shear strength (su) with liquidity index (IL) among pocket (soil) penetrometer (PP), fall-cone, laboratory vane, unconfined compression (UC), and unconsolidated-undrained triaxial compression test methods for 10 fine-grained soils investigated. Some differences between the mobilized su for testing of identically prepared samples of a given soil using different strength measurement approaches could be expected. However, the data plots presented in the original paper indicate that, depending on the IL, significantly different su values can be mobilized among several of these strength tests for a given water content — an aspect that merits critical examination. In this discussion of said paper, several observations are presented on various shortcomings in the adopted experimental methods, as reported in the original paper, and in the su – IL data analyses presented for the different strength tests investigated. Also, with the spring-operated piston of the PP device usually calibrated (by the manufacturer) using correlation studies with UC strength data, the good agreement obtained for the Authors’ PP and UC su – IL correlations would be expected.